CBS
Vicky Dawn Jackson

(CBS) Investigators have disturbed a grave site near Nocona, Texas in an attempt to solve a town mystery, reports CBS News Correspondent Maureen Maher.

Doctors say a 95-year-old Oma Wyler died on January 24 of natural causes. But investigators tell Wyler's family that she and 22 others might have died of poisoning at Nocona General Hospital. Investigators will exhume at least 11 other bodies.

"I'm still mad, I'm just so angry that someone could have done that," said Wyler's daughter Wanda Russell.

The hospital first alerted authorities to a problem in February after a pharmacist noticed that bottles of Mivacurium Chloride, or Mivacron, were missing. The drug is used to temporarily paralyze patients during emergency care, stopping the natural breathing process to relax the chest muscles. It can result in death if improperly used.

Investigators were also suspicious that the hospital's death rate for December and January had nearly doubled.

CBS News learned that Vicky Dawn Jackson was on duty when 22 of the 23 patients died - including Oma Wyler. Two lawsuits accuse the dismissed nurse of injecting patients with a lethal dose of Mivacron.

Jackson was fired from the hospital and refuses to be interviewed. The Montague County prosecutor only says that a suspect is in custody.

Another two bodies will be exhumed, but it might prove futile in solving a possible murder. Mivacron is virtually impossible to detect and the FBI says that it could take up to a year to determine whether the deaths were caused by a nurse, or by nature.

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